Improvement in artificial legs



UNITE STATES Pnrni\ir I 'erica 11 IM-PROVMENT II\I ARTIFICIAL LEGS.

Specification forming part of Letters Patent No. 38,739, dated June 2, 1863; antedated December 27, 1862.

tion represented in section. Fig. 2 is a per-v spective view of the ankle-joint device, shown detached. Fig. 3 is a detached portion of the jiinted irons H on an enlarged scale, showing the construction of the joint. Fig. 4 is a front view of the elastic knee-strap U and pad T, for connecting the upper and lower sockets.

Like lettersv designate corresponding parts in all of the figures.

My invention consists in an improved de-- vice for connecting` the ankle-joint, and also for tightening the bearing parts thereof, in the manner of constructing the joint of the sideA irons, H, for cases of amputation below the knee, and in connecting these irons with thef.

upper socket, so as to allow freedom of motion in iiexin g the leg to its greatest extent, and also in connecting the upper and lower sockets, with an elastic strap for assisting in the forward movement of the leg in walking.

As represented in the drawings, A is the foot portion of the artiicial limb 5 B,the lower socket, which receives the stump of the natural leg C, (the representation being that where the amputation is below the knee and D isl the upper socket, which receives the thigh.

A The ankle-joint is formed with a bearing, consisting of a forked piece of metal, E, having at its lower extremity a cross-pivot, f, shaped like an inverted T, which rests in a suitable bearing in the foot portion, and forms the center of motion between the foot andleg. This part is made hollow to insure lightness, and the largest part of the upright portion is bored with transverse holes to produce the same effect. The rear member, g, of the piece E is provided with a screw and shank, which pass through a plate, h, which is let into and securely fastened to the artificial leg below the socket B. A portion of this plate forms a thimble around the shank of g, above which the nut b connects the parts together. This member forms the main support of the weight of the wearer, which is received by the shoul- 'der c, resting on the plate h. The forward member, d, also enters the plate h, and may be secured to it by a nut, though this is not absolutely required. The two parts n thus arranged act, from their position, as braces inv the direction of the antero-posterior motion of the ankle-joint, that being the direction in which the greatest strain is exerted, and the pivot f, being transverse and of sufficient size and length, operates to rmly brace the joint against lateral strains. The lower side of the axis f rests in a semicireular box suitably packed with leather, horn, or other material, to prevent friction and noise. Aboveand lying directly across the journal f, on each side of the upright, are two bearing-blocks, j j, of firm wood, (shown most clearly in Fig. 2,) one end of each being secured to the foot-piece by a screw or other convenient fastening, and their opposite ends held down by the clamp-bar k with more or less force on kthe journal f. By

this device the pivotor journal f may be kept as tight as desirable to prevent noise, and may be adjusted as it becomes loose from wear by simply turning the screw l, while it also serves to regulate the freedom of motion of the joint to suit the convenience of the wearer. Back of the'forked piece E, bearing against it and a socket in the heel in adiagonal position, is a spiral spring, F, which keeps the leg in a position vertical to the foot, except when it is thrown forward and receives the weight of the person in the act of stepping,by which the spring is compressed. Its reaction (when the weight is removed) raises the toe for the succeeding step. rI he motion is limited by the forward member, d, coming in contact with the front wall of the foot at m, where provision is made against noise by packing that part with soft leather or felt. The spring F is also covered with buckskin or other material, and pins i i are provided to enter its end and prevent its becoming displaced.

When amputation is below the knee, the

artificial leg is connected to the upper or thigh socket, D, by a pairfof iron straps, H, jointed at the knee. These straps are secured rigidly to the wood of the lower portion, B, and by a single pivot, n, or equivalent means of fastening, to the upper socket, near its top. The socket D is made of two thicknesses of leather, the iron straps passing between them, and the whole are secured together by rivet n. The ordinary mode of construction is toy secure the straps to the leather by several rivets, forming a rigid connection, but I leave them entirely disconnected except at the upper end, and make the opening orfpocket in which they lie expand in width in a -downward direction, leaving the irons free tovibrate forward and back with the bending or flexing of the knee. This motion is stopped at a perpendicular position of the leg by the seam o, but when the wearer sits they drop into the position indicated by the seam p, as shown by the red lines of drawings, and relieve the upper side of the thigh from the painful pressure and strain which would otherwise be brought upon it by the pressure of the irons downward, owing to the short bend which is given to the knee. This moiiin on the pivots u enables the joints of the irons to be placed below the knee, being in consequence less in sight and not protruding when the wearer is sitting. This result is obtained by the letting of the upper iron fall below the level of its pivoted end n when the leg is in a sitting posture.

It is highly important that the joint of the irons should be so constructed as not to be# come loose by wearing, or if so, be capable of ready adjustment, so that noise will not occur from them. As I construct them to secure these results, Q is the joint-pivot, which is held in place by the screw r. The upper strap is provided with a slot, through which the pivot Q passes, and a block or bearing-piece, S, (shown most clearly in Fig. 3.) is fitted in the slot and made to press against the pivot by a screw-follower, t, which may be tn rned by any pointed instrument that will enter the holes in its sides. This follower has a screwshank, which works in the transverse screw u. By means ofthis simple arrangement the parts may always be kept tightly adjusted against the pivot Q, and this may be done with the greatest convenience by the wearer himself.

A pad, T, of leather or other suitable material, is attached to the top of the lower socket, B, and extends upward, covering the knee, to near thelower end of the upper socket. Here it connects with a piece of elastic webbing, U, or its equi-valent, that extends to the top of the upper socket, where it is attached by lacing or otherwise.

When the leg is flexed, it elongates this web, the contractile force of which, acting over the patella of the knee as a fulcrum, through the pad T, brings the foot forward as soon as raised, with little, if any, effort to the wearer, and adds much to the ease and facility of walking.

What I claim as my invention, and desire to secure by Letters Patent, is

l. The anklecoupling E, having a broad or double antero-posterior bearing, d g, connected with the leg, and transverse journal fcon nected with the foot,'arranged and operating substantially as and for the purposes set forth.

2. The means of adjusting and tightening the journal f, consisting of the bearing-pieces j j, attached to the foot, as described, together with the clamp K and adj `listing-screw l, snbstantially as set forth.

3. Connecting the jointed side irons, H, to the socket D by the pivot fn, to allow free motion or vibration thereof between the seams o p, or corresponding limits of action, substantially as shown and described.

4. The combination 'of the slot and movable bearing s, screw-follower t, and transverse screw u with the pivot Q of the jointed jside irons, substantially as and for the purposes set forth.

5. I am aware that elastic straps have been used in connection with shoulder-straps or harness for facilitating the forward motion of of the artificial leg in walking, and this I do not claim; but I claim connecting the lower portion ofthe leg, B,with the upper socket, D, by means of the elastic strap U and pad T, arranged and operating substantially as set forth.

In witness whereof I have hereunto signed 

